Establishing Visible Interferometer System Responses: Resolved and Unresolved Calibrators

The propagation of errors through the uniform disk visibility function is examined. Implications of those errors upon measures of absolute visibility through optical and near-infrared interferometers are considered within the context of using calibration stars to establish system visibilities for these instruments. We suggest a simple ratio test to establish empirically whether or not the measured visibilities produced by such an instrument are relative (errors dominated by calibrator angular size prediction error) or absolute (errors dominated by measurement error).Comment: 20 pages, 7 figures, to be published in the PAS

Spitzer Space Telescope Observations of Circumbinary Dust Disks around Polars

We present Spitzer Space Telescope IRAC photometry of the magnetic cataclysmic variables EF Eri, MR Ser, VV Pup, V834 Cen, GG Leo and V347 Pav. When we combine our results with the 2MASS data, we find that at least five of the polars have flux densities in the mid-IR in excess of the emission expected from the stellar components alone. We are unable to model this mid-IR excess with cyclotron emission, but we can recreate the observed spectral energy distributions with the inclusion of a simple circumbinary dust disk model. Importantly, we find that the masses of our modelled disks are approximately 12 orders of magnitude lower than required to significantly affect CV evolution. The accretion disk-less polars are ideal places to search for these disks, since the luminous accretion disk in most CVs would drown out the faint IR signature of the cooler, dimmer circumbinary disks

Multistakeholder Perspectives on Maternal Text Messaging Intervention in Uganda: Qualitative Study

Background: Despite continued interest in the use of mobile health for improving maternal health outcomes, there have been limited attempts to identify relevant program theories. Objectives: This study had two aims: first, to explicate the assumptions of program designers, which we call the program theory and second, to contrast this program theory with empirical data to gain a better understanding of mechanisms, facilitators, and barriers related to the program outcomes. Methods: To achieve the aforementioned objectives, we conducted a retrospective qualitative study of a text messaging (short message service) platform geared at improving individual maternal health outcomes in Uganda. Through interviews with program designers (n=3), we elicited 3 main designers’ assumptions and explored these against data from qualitative interviews with primary beneficiaries (n=26; 15 women and 11 men) and health service providers (n=6), as well as 6 focus group discussions with village health team members (n=50) who were all involved in the program. Results: Our study results highlighted that while the program designers’ assumptions were appropriate, additional mechanisms and contextual factors, such as the importance of incentives for village health team members, mobile phone ownership, and health system factors should have been considered. Conclusions: Our results indicate that text messages could be an effective part of a more comprehensive maternal health program when context and system barriers are identified and addressed in the program theories

Insights on the Role of Diabetes and Geographic Variation in Patients with Criticial Limb Ischaemia

AbstractBackgroundPatients with critical limb ischaemia (CLI) unsuitable for revascularisation have a high rate of amputation and mortality (30% and 25% at 1 year, respectively). Localised gene therapy using plasmid DNA encoding acidic fibroblast growth factor (NV1FGF, riferminogene pecaplasmid) has showed an increased amputation-free survival in a phase II trial. This article provides the rationale, design and baseline characteristics of CLI patients enrolled in the pivotal phase III trial (EFC6145/TAMARIS).MethodsAn international, double-blind, placebo-controlled, randomised study composed of 525 CLI patients recruited from 170 sites worldwide who were unsuitable for revascularisation and had non-healing skin lesions was carried out to evaluate the potential benefit of repeated intramuscular administration of NV1FGF. Randomisation was stratified by country and by diabetic status.ResultsThe mean age of the study cohort was 70 ± 10 years, and included 70% males and 53% diabetic patients. Fifty-four percent of the patients had previous lower-extremity revascularisation and 22% had previous minor amputation of the index leg. In 94% of the patients, the index leg had distal occlusive disease affecting arteries below the knee. Statins were prescribed for 54% of the patients, and anti-platelet drugs for 80%. Variation in region of origin resulted in only minor demographic imbalance. Similarly, while diabetic status was associated with a frequent history of coronary artery disease, it had little impact on limb haemodynamics and vascular lesions.ConclusionsClinical characteristics and vascular anatomy of CLI patients with ischaemic skin lesions who were unsuitable for revascularisation therapy show little variations by region of origin and diabetic status. The findings from this large CLI cohort will contribute to our understanding of this disease process.This study is registered with ClinicalTrials.gov, number NCT00566657

Young Low-Mass Stars and Brown Dwarfs in IC 348

I present new results from a continuing program to identify and characterize the low-mass stellar and substellar populations in the young cluster IC 348 (1-10~Myr). Optical spectroscopy has revealed young objects with spectral types as late as M8.25. The intrinsic J-H and H-K colors of these sources are dwarf-like, whereas the R-I and I-J colors appear intermediate between the colors of dwarfs and giants. Furthermore, the spectra from 6500 to 9500 A are reproduced well with averages of standard dwarf and giant spectra, suggesting that such averages should be used in the classification of young late-type sources. An H-R diagram is constructed for the low-mass population in IC 348 (K6-M8). The presumably coeval components of the young quadruple system GG~Tau (White et al.) and the locus of stars in IC 348 are used as empirical isochrones to test the theoretical evolutionary models. For the models of Baraffe et al., an adjustment of the temperature scale to progressively warmer temperatures at later M types, intermediate between dwarfs and giants, brings all components of GG~Tau onto the same model isochrone and gives the population of IC 348 a constant age and age spread as a function of mass. When other observational constraints are considered, such as the dynamical masses of GM~Aur, DM~Tau, and GG~Tau~A, the models of Baraffe et al. are the most consistent with observations of young systems. With compatible temperature scales, the models of both D'Antona & Mazzitelli and Baraffe et al. suggest that the hydrogen burning mass limit occurs near M6 at ages of <10 Myr. Thus, several likely brown dwarfs are discovered in this study of IC 348, with masses down to ~20-30 M_J.Comment: 23 pages, 9 figures, accepted to Ap

Targeting strategies of mHealth interventions for maternal health in low and middle-income countries: a systematic review protocol

INTRODUCTION: Recently, there has been a steady increase in mobile health (mHealth) interventions aimed at improving maternal health of women in low-income and middle-income countries. While there is evidence indicating that these interventions contribute to improvements in maternal health outcomes, other studies indicate inconclusive results. This uncertainty has raised additional questions, one of which pertains to the role of targeting strategies in implementing mHealth interventions and the focus on pregnant women and health workers as target groups. This review aims to assess who is targeted in different mHealth interventions and the importance of targeting strategies in maternal mHealth interventions. METHODS AND ANALYSIS: We will search for peer-reviewed, English-language literature published between 1999 and July 2017 in PubMed, Web of Knowledge (Science Direct, EMBASE) and Cochrane Central Registers of Controlled Trials. The study scope is defined by the Population, Intervention, Comparison and Outcomes framework: P, community members with maternal or reproductive needs; I, electronic health or mHealth programmes geared at improving maternal or reproductive health; C, other non-electronic health or mHealth-based interventions; O, maternal health measures including family planning, antenatal care attendance, health facility delivery and postnatal care attendance. ETHICS AND DISSEMINATION: This study is a review of already published or publicly available data and needs no ethical approval. Review results will be published in a peer-reviewed journal and presented at international conferences. PROSPERO REGISTRATION NUMBER: CRD42017072280